Register sender circuit



Sept 29, 1964 P. H. ARNOLD ETAL 3,151,220

REGISTER SENDER CIRCUIT 7 Sheets-Sheet l Filed May 11, 1961 ATTORNEY Sept- 29, 1964 P, H. ARNOLD ETAL 3,151,220

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P. H. Ae/vo/ o R. H. VEHME/ER /NVENTORS v ...gl

ATTORNEY SePt- 29 1964 P. H. ARNOLD ETAL 3,151,220

REGISTER sENDER cIRcurT 7 'Sheets-Sheet 5 Filed May 1l, 1961 m@ Arrow/EV Sept 29, 1964 P. H. ARNOLD ETAL 3,151,220

REGISTER SENDER CIRCUIT 7 Sheets-Sheet 6 Filed May ll, 1961 @E gov Nwq AT TORNEV Sept. 29, 1964 P. H. ARNOLD ETAL 3,151,220

` REGISTER SENDER CIRCUIT Filed May ll, 1961 7 Sheets-Sheet 7 ArroRA/V United States Patent O 3,151,220 REGETER SENDER CliRCUlT Philip H. Arnold, ii/ieiratunlr, NJ., and Robert H. Vehnreien Brooklyn, NPY., assignors te Bell Telephone Laboratories, incorporated, New York, NX., a corporation et New York Filed May l1, 196i, Ser. No. 09,444 lfdlaims. (Cl. 179-47) This invention relates to a register sender circuit` and more particularly to such a circuit for converting pushbutton codes into pulse trains.

The function or the so-called rotary dial7 in automatic telephone switching systems is of course well established; as is well understood in the art this device, when operated by the subscriber or PBX attendant, serves to originate the pulse trains which, in turn, direct the selectors, connectors, or other switching circuits to extend the connection to the called party whose number was dialed. The rotary dial is commonly provided with a governor which exactly controls the speed of each return rotation (during which the impulses are transmitted) whereby to assure the uniformity in the pulse trains required for proper response by the associated switching equipment. The pulses may be transmitted at a rate of ten pulses per second for calls to a subscriber, by way of example, and at a rate of twenty pulses per second for calls to a direct dial central ollice trunk.

ln recent years, and in a relatively limited number of installations, the rotary dial has been supplanted by socalled pushbutton dials or pushbutton call transmitters; by use of these devices the called number is transmitted simply by depressing the proper buttons, and many telephone subscribers feel that faster and more convenient dialing results from their use. Also, this type of call` transmitter has proven particularly adaptable for use at iBX attendants positions; this particular application will be described herein as illustrative of one possible use.

One type of pushbutton dialer which is used in these installations, and in connection with which our invention will be disclosed, operates on a two-out-o-ve code; that is live dial code leads are provided, commonly` being designated 6; 'l, 2, 4l and 7, and for each digit dialed ground is applied to two out of these live leads according to the particular digit dialed. Now it will be apparent that, in order to permit the use of the conventional selectors, connectors and other switching equipment, it will be necessary to convert these various twoout-of-iive codes into pulse trains of the nature produced by the standard rotary dial. (The term dialed as used herein is intended to contemplate, when appropriate, the transmission of a called number by a pushbutton calling device.)

Accordingly, it is an object of our invention to improve the originating and transmitting of calling information.

Another object ci the invention is to convert pushbutton call transmitter codes into dial pulse trains.

Still another object of the invention is to automatically change on occasion the pulse transmission from a first definite rate to a second definite rate.

A still further object of the invention is to render feasile the recording of a larger than normal number of digits with only the normal number of digit storage units.

According to a speciic embodiment of our invention a register sender capable of registering up to twelve digit number calls utilizes only the usual seven digit register units in the storage circuit. When a subscriber, or attendant, pushbutton dials a number, ground is applied to two of the iive dial code leads, 6, L 2, 4 and 7. Each two-out-oi-five code is steered to a register unit in the storage circuit. Stored information is passed on to units after the seventh digit has been dialed.. Means are` also provided` f or guarding against a premature release of, these storage units inthe event` the attendants dialing speedl is substantially fasten than the outpulsing speed. A feature of the invention isimeans eiiectiye when 9 is diaied for a central oice trunlctorr changing the pulse transmission fromarate ofV 1013,35. to 20 PRS.

Another featurel of theinventionislvisual means, also effective when 9 is dialed, for indicating when dial` tone has been obtained and the remaining digits maybe dialed.

A further feature of the invention is means` for recycling the first steering` relay, which was used when @was dialed, so that` the rst digit or" the called number will be registered in the first unit of the storage circuit.

A still further feature of the invention is visual means energized in the event the sixth digit is pushbutton dialed before the fourth registered digit is being outpulsed whereby to indicate a too-rapid dialing speed.

Yet another feature of the invention is means` forV preventing recycling ofthe circuit, which normally occurs after transmission of the seventh digit, unless, and until, outpulsing from the circuit has reached a predetermined stage.

A full understanding of the arrangement contemplated by the present invention as well as an appreciation of the various advantageous features thereof may be gained. from consideration of the following detailed description in connection with the accompanying drawing, in which:

FiG. l shows schematically Aone way in which the register sender circuit contemplated by` the present invention may be associated with other portions of a telephone System; v

FIG. 2 shows schematically the relationship of the various individual circuits which comprise one specific illustraive embodiment of the register sender contemplated by the invention;

FIG. 3 shows paricularly the steering circuit of the register sender;

FlG, 4 shows the storage circuit of theregister sender, one of the register units being illustrated in detail and the others beingindicated schematically;

FlG. 5 shows the recycle4 and end-of-pulse train circuits of the register sender;

FIG. 6 shows the clear circuit, the sequential digit selector circuit, the translator circuit, and the interdigital timing circuit of the register sender;

FIG. 7 shows the pulse counter circuit and the pulse generator circuits of the register sender;

FIG. 8 shows the central office trunk testing circuit, trouble linder circuit, seizure circuit, release circuit, all senders busy circuit and register sender linlr timing -recycle circuit of the register sender; and

FIG. 9. shows the manner in which the tigures should be joined when in use.

Referring now to the drawings, and iirst particularly to FIG. 1, a pushbutton` call transmitter 31 is shown, being located for example at the attendants` position of a private branch exchange, and connected by way of register sender link circuit 34 to` register sender 32, over suitable leads including five dial code leads designated respectively 0, 1, 2, d and 7. Connections are also provided from the register sender to sender group 33. At-

tendants lamp 35 is provided at the attendants position preferably being located adjacent to pushbutton call transmitter 31. It will be understood that the attendants position circuit will be connected in the usual manner to a cord circuit or similar circuit.

Pushbutton call transmitter 31 and register sender link circuit 34 will not be described in detail herein since the present invention is not concerned with the specific arrangement of those items, but only with certain of the overall operations thereof which will be referred to in general terms. Call transmitter 31 may be any one of several general arrangements now available which operate on a two-out-of-ve code basis; that is depression of a digit button or key results in connection of ground to a particular two of the five dial code leads depending upon the digit dialed In a manner described subsequently these codes from call transmitter 31 are converted in register sender 32 to either 10 P.P.S. or 20 P.P.S. trains and the pulse trains are transmitted into the connecting circuit.

Register sender link circuit 34 may be arranged through use of suitable multiple connecting means such, for eX- ample, as a D-point crossbar switch, to serve a plurality of register senders, for example ten, and a plurality of positions, for example twenty. When ground is applied to the ST lead by operation of the start (S) button of the call transmitter, the register sender link circuit functions to connect an idle register sender to the attendants position involved; when the register sender completes its function it signals back -to the position circuit (as described in detail subsequently) which, in turn, removes the ground from the ST lead and releases the register sender link circuit and opens the connection between the position circuit and the associated register sender. When the -register sender link circuit has selected an idle register sender andcompleted its connecting function, the various indicated leads from the position circuit, with the exceptions of the ST and RL leads, are connected through the register sender link circuit to the register sender.

General Description The arrangement and operation of the various components of register sender 32 will be described in detail subsequently in connection with FIGS. 3 to 8, inclusive, However, in order to first gain a general overall understanding of the arrangement, a brief general description will be given at this point with reference to FIG. 2. Assuming that the register sender 32 has been connected to the pushbutton dial circuit by register sender link circuit 34 in response to a start signal transmitted by operation of the S button of transmitter 31, and that the attendant is signaled to start dialing by the steadily lightedV lamp signal 35, she then proceeds to pushbutton dial the number into register sender 32. As previously pointed out, for each button operation ground is applied to two of the live dial code leads. Each two-out-of-iive code is directed by steering circuit 41 to the proper regis- Vter unit of storage circuit 42. Each register unit preferably comprises a relay with tive independent coils, each coil encompassing two glass enclosed dry reed switch contacts. The received code operates two of the iive sets of reed switches which lock up under control of the sequential digit selector circuit 43.

Information stored, as above described, in storage circuit 42 is passed along to translator circuit 44 which thereupon conditions pulse counter circuit 47 and starts a cycle in interdigital timing circuit 48. At the end of the timing cycle, pulse generator 61 starts outpulsing, the pulses being counted by pulse counter circuit 47. When pulse counter circuit 47 has counted the particular number of pulses for which it has Vbeen conditioned, it activates end-of-pulse train circuit 62 which acts to stop the pulse train and release the information in translator circuit 44. The end-ofpulse train circuit 62 then signals the sequential digit selector circuit 43 causing it to step to the next storage circuit register unit. This process is repeated for each digit until an end-of-code signal is transmitted by storage circuit i2 which causes translator circuit 44 to operate a rrelease relay, operation `of which Vis effective to release the register sender.

As clearly brought out in the subsequent detailed description, the novel arrangement provided is such that, in the event a long number, for example one of eleven digits, is being dialed, a recycling operation normally takes place, after the seventh digit has been transmitted, and the rst live storage units are cleared for reuse with the remaining digits of the number. However, a novel guarding means is provided Vfor preventing a premature release of these storage circuits, that is, premature in the sense that the attendants dialing progress has substantially outdistanced the outpulsing progress of the register sender.

Other novel arrangements contemplated by the invention will also be clear from the subsequent detailed description such, for example, as the operation of attendants lamp 35, at iiutter for two different purposes,

first, at the initiation of a dial 9 call as a wait for dial tone warning, and, second, during the dialing operation to warn the attendant if her dialing speed is too much faster than the outpulsing rate, this warning signal being given if the sixth digit is pushbutton dialed before the fourth digit has been outpulsed. In accordance with the novel arrangement contemplated, which will be described in detail subsequently, even though the attendant disregards the warning and continues to dial, recycling which ordinarily occurs after transmission of the seventh digit, is prevented until the outpulsing reaches the proper point.

Derailed Description For a detailed description of the spcciiic illustrative embodiment of the invention we will now assume that the attendant is preparing to pushbutton dial a number from her position by means of transmitter 31 (FIG. l) and, further, that it is to be a central oiiice trunk call. A signal transmitted from the attendants position circuit by operation of the S (start) key, which applies ground to the ST (start) lead, causes the register sender link circuit to function and to connect the pushbutton call transmitter 31 through to an idle register sender 32. At this time ground is applied from the register sender link circuit over lead (2S-36 to operate relay CS of the seizure circuit (FIG. 8).

Relay CS, operated applies ground through its make contact CS-l to lead MB-de (release circuit, FIG. 8) and through its make contact CS-2 to lead (2T-63 (pulse generator, FIG. 7), both of which leads connect to the register sender link circuit, closes through its CS-3 make contact a shunt path in the All Senders Busy chain (FIG. 8), and completes a path for operation of relay PS (FIG. 7) traced from battery, winding of relay PS, break contact IDC-1 of relay llDC, make contact CS-4 of relay CS to ground.

Closure of ground through lead CT-63 to the register sender link circuit 34 causes that circuit to cause lamp 35 at the attendants position to light steady as an indication to the attendant that the register sender 32 (FIG. l) is in condition to receive pushbutton dial pulses. Relay CS, operated, also completes at its make contact CS-24 a path for operation of relay CLA (FIG. 8), from ground supplied over lead CLA-65, to indicate the connection of a sender to the switchboard position.

Attendant Dials "9 As pointed out above, it is being assumed irst that the attendant wishes to be connected to a direct dial central otlice trunk and, accordingly, when she is appraised by steadily lighted lamp 35 that the register sender is ready to receive pulses, she depresses the 9 digit button of call transmitter 31 thereby grounding digit leads 7 and 2 which pass through register sender link circuit 34 to the register sender 32.

It should be pointed out here that for purposes of simplification and clarity, there has been shown in detail only one storage unit ARS (FlG. 4); it will be understood that six other similar storage units BRS to GRS inclusive are provided, these are indicated simply by captioned rectangles. A similar simplification of the multipled digit leads and of the digit selecting relays lll-D7, has been carried out in FIG. 3 and in these two figures; as well as in FIGS. 5 and 6, dot-dash lines with brackets are utilized in an obvious manner to show the carrying over or,` groups of leads from one point to another.

Returning now to circuit operations following application of ground to digit leads 2 and 7, the ground on lead A2 (FG. 3) causes operation of relay ARZ of the ARSA storage unit (FIG. 4) while, similarly, the ground on lead A7 causes operation of relay AR? oi the same storage unit. Also, following the dot-dash and bracketed indications, the ground on lead A2 causes operation of relay T2 of the translator (FlG. 6), and the ground on lead A7 causes operation of relay T7 of the translator together with relay RT (FIC. 3).

Relay ARZ, upon operating, locks over a path from battery, its operating winding and make contact AEZ-2, lead L1, break contacts RC-l of relay RC and DTi-S of relay DT?. (recycle circuit, FIG. 5), make Contact CS-13 of relay CS to ground. Similarly, relay AR7, upon operating, locks through its make contact ATU-2 over this same path.

Relay RT, operated, opens at its break contacts RT-i and RT-Z respectively digit leads 2 and 7, whereby to prevent possible double digit registration, and also completes an obvious path through its make contact RT- 3 for operation oi relay l of the register sender link timing recycle circuit (FlG. 8); operation of relay K in turn connects battery through its make contact K-l over lead 67 to the register sender link circuit causing a time alarm circuit included therein to function. Digit leads tij l and 4 are also opened by operation of relay RT at respective break contacts RT-S, RT-o and RT-7. Relay RT, upon operating also closes at its make contact RT-4 a path for supply of battery potential to the operating windings of the seven-digit steering relays Dl to D7 (FlG. 3), four of which Dl, D2, D5 and D7 are shown as typical of all seven.

The lirst digit steering relay D1 operates at this time over a path from battery, make contact RT-4 of relay RT, break Contact D'l-l and operating Winding of relay D1, lead L27, make contacts ARZ-l of relay ARQ and 7-ll of relay AR', lead Ll, break contacts RC-l of relay RC and DTi-S of relay DTl (FlG. 5), make contact CS-l3 of relay CS to ground; relay Dl upon operating locks to this same path through its make contacts Dl-ld and D145.

Relay D1, operated, interrupts at its break contacts Dl-Z, Dl-S, Died, Dl-S and Dl-d the connection of the digit leads to the ARS storage unit, and closes at its make contacts Dil-7, Dl-, Dl-, Dlt-lil and Dlt-lll paths through break contacts DZ-Z, DZ-S, D22-d, B2-5 and Dfi-t5 of relay D2 for connection of these digit leads to the second storage unit BRS for subsequent storage of the second digit.

lt will be understood that the other digit selecting relays D2 to D7 operate in turn, over paths similar to that described in connection with relay D1, as the paths are completed in turn by operation of relays in the respective storage units. This assures that each subsequent digit will be steered in turn to the proper respective storage unit. However, a novel feature of the present invention should be noted here whereby, when a dial 9 call is initiated and the digit 9 is stored in the first storage unit, the circuit is in erlect recycled so that the lirst digit of the actual number when dialed will be stored in the first storage unit ARS rather than in the second. This is accomplished by the inclusion in the operating paths for the digit selecting relays, as described above, break contacts DTI-S of relay DTl and DT-7 of relay DT; relays DTI and DT are in operated condition in connection with the seizure of a central office trunk in response to dial 9 and the stepping path for t-e digit steering relays is therefore open and the digit leads remain connected to the tirst storage unit ARS.

Operation of the translator relays T2 and T7 as mentioned above opens at their respective T22-1 and T74 break contacts the path over which battery was supplied to start anode 68 of the interdigital timing gas tube 7l (FIG. 6); operation of relays T2 and T7 also completes a path for operation of relay DT of the central oilice truuk testing circuit (PEG. 8), this path being traced from battery, winding of relay DT, make contacts 'T2-2 ol relay T2 and 'T7-2 of relay T7, break contacts SSI-l of relay SSl and DTi-l of relay DTT, make contact CS- of relay CS to ground;

it should be noted here that relay DT is an essential part of the arrangement involving one function of attendants lamp 35 (FlG. l), that is causing the lamp to light at utter as an indication to the attendant not to dial further until the central office conditions itself for pulses, that is in eliect until dial tone is present.

Relay DT, operated, completes a path from liutter circuit '72 (FlG. 5), which includes a source of ground interrupted at the desired iiutter rate, make contact lDT-Z` of relay DT, break contact TF-l oi relay TF, make contacts CS-6 of relays CS, lead lill-73 to the register sender link circuit 3d and thence to attendants lamp 35' which is caused to light at Hutter as a stop dial indication to the attendant until the central o'ice trunk has conditioned itself to receive pulses.

lmerdz'gital Timing As pointed out above operation of translator relays T2 and T9 resulted in removal or the negative battery potential from start anode 68 of the timing tube il (PlG. 6); this triggers and starts operation of the interdigital timing circuit. Capacitor '74 which is connected from start anode 63 of gas tube 7l to ground through break contact CL-l of relay CL and limiting resistor 77, is charged from positive battery potential, make contact CS- or relay CS, break Contact PC-l of relay PC, winding orP relay IDC, break contacts lDC-Z of relay lDC and Cla-2 of relay CL, and through resistors 78 and 9i and potentiornetei` 92 in series. Potentiometer 92 may be adjusted to tix the interdigital time in this instance at approximately 7G() milliseconds (as will be brought out subsequently this period is changed after 9 has been dialed).

When capacitor 7d has been charged to a sufficient value for breakdown voltage across the start gap of tube 7l, the tube tires and relay TDC is operated by the current flowing through the main gap or" the tube. Relay lDC, operated, holds to ground through its make contact lDC-E, extinguishes tube 7l by opening the current path at its break contact lDC-Z, connects negative battery potential through its make contact TDC-4 to start anode 68 of tube 7l, opens at its break contact lDC-l the shunt path around break Contact P-l and make contact P-f ot relay P (FTC. 7), and completes a path through its make Contact lDC-S for starting the pulse generator (FlG. 7).

Sender test key TSK, nonlocking (FlG. 3) with make contacts TSl-l and TSK-Z may be used in preliminary adjustment of potentiometer 92.

Pulse Generating When relay lDC operates, as above described, ground is applied through its make Contact EDC-5 and break contact P-3 of relay P to relay PG which is a two-winding, polar relay, preferably provided with mercury contacts (FIG. 7). Relays PG and P together constitute a self interrupting pulsing circuit; the timing of the pulses is controlled by suitably selected capacitors 93 and 94 and resistors 97, 98, lltll and 162. The secondary winding of relay PG is connected at both ends to negative battery through respective resistors I lll and lill The two windings of the PG relay are preferably wound in opposition to each other with the negative terminal of the primary winding connected to the positive terminal of the secondary winding and the positive terminal of the primary Winding connected to the capacitors 93 and 9d.

With relay P normal, i.e., released, current is applied to the secondary winding of relay PG in the direction to operate the relay but this action is opposed by the current in the primary winding which is charging capacitor 93. As the charging current reduces toward zero, the secondary winding will cause operation of relay PG. Relay PG, operated, completes through its make contacts PG-l and PG-Z an obvious operating path for relay P; relay P by its operation in eitect transposes at its break contact P-S and make contact P4 the battery and ground connections to the primary and secondary circuits of relay PG. The current in the secondary winding of relay PG will now be in the direction to cause the relay to release, but since capacitors 93 and 94 will charge in the reverse direction tending to hold the relay operated, release of the relay will be delayed until the current in the secondary winding builds up suliciently. When relay PG releases, relay P also releases and the lirst described conditions of the circuit are restored. The duration of the operated-released positions of relay PG is determined by the Values of the resistors; in general increasing the value of resistor 97 will decrease the pulse speed While increasing the value of resistor lill will decrease the percent break.

Relay P by its operate-nonoperate action sends pulses out over the tip conductor 121 and ring conductor 122 (FIG. 8) by opening and closing the pulsing loop at its make contact P-6.

Since the lirst pulse produced by the pulse generator will be distorted due to the fact that capacitors 93 and 94 are starting to charge from Zero voltage, it is desirable that this pulse be shorted out. This is accomplished through the PS relay (FIG, 7) which, as pointed out above, operated following the operation of the CS relay. Relay PS upon operating locks over a path from battery, winding and make contact PS-ll of relay PS, break contact P- of relay P, make contact CS-4 of relay CS to ground, and does not release therefore upon operation of relay RDC. While relay PS is operated the pulse input path to the pulse counter circuit (FIG. 7) is open at break contact lS-Z of relay PS so that the lirst pulse (While relay PS is still operated) is not applied to the pulse counter circuit and is not counted; also, the pulse is not transmitted since the line loop pulsing contact P-d of relay P is shunted by make contact PS-fl of relay PS (FIG. 8). However, after production of the initial pulse, relay P operates as above described, the holding path for relay PS is opened at break contact P-l of relay P, relay PS releases and the input path to the pulse counter is closed at break contact PS-Z of relay PS.

Pulse Counting and End-,of-Pulse Operation The pulse counter (FIG. 7) is a l0-pulse, partially recycling, counter which utilizes siX relays designated according to the pulses by which they are operated; i.e., relay E14-7 is operated by the lirst and seventh pulses, relay ES-l-Q by the third and ninth pulses and so on. The pulses produced by the pulse generator are divided by pulse dividing relays W and Z of the pulse counter circuit before being counted by the counting relays El-lthrough E5. The relays continue to divide pulses issuing from the P relay until the PC relay operates at the end of the pulse train as subsequently described.

Relay W operates when relay P operates (and after relay PS has released following the initial pulse) over a path from battery, break contact PC-Z of relay PC, winding of relay W, break Contact Z-l of relay Z, make contact P-Ll ot relay P, break contact PS-2 of relay PS, make contact IDC-6 of relay lDC to ground, following which relay Z operates when relay P releases over a path from battery, break contact PC-2 of relay PC, winding and break contact Z-Z of relay Z, make contact W-Z of relay W, break contact P-S of relay P, break contact PS-Z of relay PS, make contact llDC- of relay lDC to ground; the W relay is temporarily held through make contact Z-3 of relay Z and its own make contact W-Z, but releases upon the second operation of relay P which interrupts this temporary holding path at its break contact P-S. While relay W is held, a holding path for relay Z is established through its operating winding and make contact 2 4, make contacts W-a of relay W and )LDC-8 of relay IDC to ground. After relay W releases, relay Z is temporarily held over a path through its Z-i make contact and lead M33, but releases on the second release or relay P since the temporary holding path is then opened at make contact P-4 of relay P. The entire operation now repeats; thus when the Z relay operates an odd pulse is sent to the counter and an even pulse is sent when the Z relay releases.

Because of the operation of translator relays T2 and T7 (dial 9), all make contacts of these two relays will be operated in the end-o-pulse circuit (FIG. 5) wherebyV to properly mark this circuit; specifically the make contacts involved are make contacts T2-7 and 'T2-8 of relay T2 and make contacts 'T7-d, T7-7 and 'T7-8 of relay T7. The end-of-pulse circuit is now set to count nine pulses in the pulse counter circuit (PIG. 7).

When relay Z is in operated position as above described, relay E14-7 will operate to count the first pulse over a path from battery, make contact CS-ZZ of relay CS, break contact PC4 of relay PC, winding of relay El-lJ, break contacts ES-l of relay E5, ES-l-Sl-l of relay ES-l-ll, E24-8 1 of relay E24-8, and Edd-0 1 of relay Ell-l-t), make contacts Z-S of relay Z and IDC-6 of relay lDC to ground; relay ELI-7 upon operating locks to ground through its make contact E14-7 1, break contacts EZ-i-S-Z of relay EZ-l-S, E34-9 2 of relay E3-l-9, El-HLZ of relay PAH-0, and ES-Z of relay E5 and make contact lDC- of relay IDC.

Now when relay Z releases, relay E24-S will operate to count the second pulse over a path from battery, make contact CS-ZZ of relay CS, break contact PC-t of relay PC, winding of relay E24-8, make contact El-i-7-2 of relay Eil-k7, break contact Z-6 of relay Z, make contact lDC- of relay lDC to ground; relay EZ-I-S upon operating locks through its make contact E-ll-S to the ground on make Contact IDC-6 of relay IDC and at the same time interrupts at its break contact EZ-l--Z the holding path for relay E14-7 which thereupon releases.

When relay Z next operates, relay E34-9 operates to count the third pulse over a path from battery, make contact CS-ZZ of relay CS, break contact PC-4 of relay PC, winding of relay E34-9, make contact E2+S4 of relay EZ-Hl, break contact E4-l-tl-1 of relay Ell-Hl, make contacts Z-S of relay Z and H3C-6 of relay IDC to ground; relay E34-9 upon operating locks to ground through its make contact E3-l-9-3 and interrupts at its E3+92 break contact the holding path for relay E24-3 which thereupon releases.

Upon release of relay Z, relay E4|0 operates to count the fourth pulse over a path from battery, make contact CSJZ of relay CS, make contact PC-4 of relay PC, winding or" relay Ei-l-ll, make contact E34-9 4 of relay E34-9, break contacts E14-7 3 of relay Eli-7 and Z-6 of relay Z, make Contact 1DC6 of relay lDC to ground; relay Ell-Hl, upon operating, locks to ground through its make contact E4+tl3 and interrupts at its EL34-0 2 break contact the holding path for relay E34-9 which releases.

Next, upon reoperation of relay Z, relay ES operates to count the fifth pulse over a path from battery, make conact CS-ZZ of relay CS, break contact PC-4 of relay PC, winding of relay E5, make contact E4-l-(l-4 of relay Ell-l-ll, make contacts Z-S of relay Z and 1DC6 of relay lDC to ground; relay E upon operating locks over a path through break Contact El-l-'-l of relay E14-7, its own make contact E523 make contact H3C-6 of relay lDC to ground and interrupts at its break contact ES-Z the holding path for relay Ell-ttl which releases. Relay ES, operated, also interrupts at its break contact ES-l one of the shunt paths to the winding of relay lil-F7.

Relay E6 operates to `count the sixth pulse, when relay Z next releases, over a path from battery, make contact CS-ZZ of relay CS, break contact PC-4 of relay PC, winding of relay E6, make contact lid-4 of relay E5, break contacts Ehi-'7 3 of relay E14-'7 and .ZC-6 of relay Z, make contact lDC-ti of relay lDC to ground; relay E6 upon operating holds operated through its make contact E46-1 and make contact lDC-6 of relay lDC to groundV until the circuit is subsequently released by the operation of relay PC after which relay lDC releases.

Relay E6, operated, partially reestablishes at its S-Z make Contact the operating path for relay Eid-7 for subsequent operation on the seventh pulse.

Relay El-' again operates, this time to count the seventh pulse, when relay Z reoperates, over a path from battery, make contact CS-ZZ ot relay CS, break contact PC-l` of relay PC, winding of relay E14-7, make contact Eli-2 of relay En, break contacts E34-9 1 of relay E34-9, EZ-l--l of relay E24-S, and Eli-l-tl-l of relay Ei-l-lltl, make contacts Z-s" of relay Z and llDC- of relay lDC to ground; upon operating, relay E14-7 locks as before through its El-l-7-l make contact. Relay E5 releases at this point as its holding path is interrupted at break contact E-l--l of relay BSH-7.

Over paths previously traced, relays ELI-8 and E34-9 will now operate in turn to count the eighth and ninth pulses, relay El-l-' releasing upon operation of relay EZ-l-S and relay E24-3 releasing upon operation of relay E34-9. Relay E34-, as before, locks through its ES-f-Sl-B make contact. At this point since the nine pulses have been counted we should nd a path completed in the endet-pulse circuit (FG. 5) for terminating the pulsing; as stated above all make contacts of relays T2 and T7 are closed, since these two translator relays are operated, and a path is completed, therefore, for operation of relay PC which is traced from battery, make contact CS23 of relay CS, operating winding of relay PC, break contacts El-l-7-5 of relay Ela-7 and E24-8 5 of relay EZ-l-S, make contact E34-$5 ot relay S34-9, break contacts Eft--l-tl-S of relay Ell-Hl and E5-5 of relay E5, make contacts lin-3 of relay E6, T745 oi relay T7 and rl`2-7 oi relay T2 to ground. Relay PC, upon operating, will lock over a path from battery, make contact CS-23 of relay CS, its operating winding and make contact PC-7, make contact 534-9-5 of relay E3+9 to ground; an alternate locking path to ground is also provided through make contact lDC-7 of relay EDC. Relay PC, operated, operates through its PC-6 make contact relay PCS and also performs other functions which will be described below.

lt is believed that the functioning of the pulse counter in counting other numbers of pulses will be clear from the above description of counting nine pulses and that the accompanying operation of the end-of-pulse circuit will likewise be clear. For example, assuming that the digit 4 were dialed, relay ld-H) oi the pulse counter would ultimately be operated and locked while relays Til and T4 of the translator would be operated with consequent closure in the end-ofpulse circuit of make contacts Tft-f and Tl-5 of relay Trl and make contacts TiMi, Til-5, Til-6, and TllJ of relay Til. Thus, upon opera* tion of relay 544-0 in counting the fourth pulse, a path is completed for operation of relay PC traced from battery, make Contact CS-23 of relay CS, winding of relay PC, bieak contacts El+7-5 of relay El-{-7, E24-8 5 of relay E24-8, E3+6 of relay ES-l-Q, make contact E4+6 of relay Edd-tl, break contacts E5-5 of relay ES and Eri-4 of relay E6, make contacts TllJl of relay 11G' T0 and T4v5 of relay T4 to ground. Relay PC operates and locks to ground through its make contact PC-7 and make contact E4+0-7 of relay E4-l-7.

Relay PC, operated, provides a locking path for relay P (FIG. 7) traced from battery, winding and make contact PJ of relay P, make contact PC-S of relay PC to ground; by so arranging the circuit that relay PC is energized during the last pulse break interval. and thereby providing a locking path for the P relay, a complete cycle of make intervalplus break interval is made available for ending the pulse train.

The translator circuit (FIG. 6) comprises relays Til,

T1, T2, T4 and T7 which are operated in twooutof-live manner from the code information supplied to the storage units and transmited under control of the sequential digit selector circuit. The information is translated into one out of ten code information which is applied to the pulse counter as above.

. Following the completion or" each digit the PC relay operates as already stated above and removes at its PC-3 break contact the common battery of the translator relays (PTG. 6), removes at its PC-4 break Contact the common battery of the pulse counter relays (FlG. 7), and opens at its PC-ll break contact one of the shunt holding paths for relay IDC (FIG. 6) which is now held through break contact PS-3 of relay PS. Now when the P relay operates to complete the last pulse of the digit, it operates the PS relay (FIG. 7) over a path from battery, winding of relay PS, make Contact PC-S of relay PC and make Contact P-2 of relay P, make contact CS-4 of relay CS to ground. Operation of relay PS interrupts at its break contact PS-S the alternate holding path for relay lDC (FIG. 6) which releases.

Relay lDC upon releasing opens at its IDC-7 make contact the holding path for relay PC (FlG. 5) which releases (assuming all pulse counter relays released); release of relay PC in turn opens at its PC-d make contact the operating path for relay PCS which subsequently releases. Relay PCS is made slow to release whereby to insure suldcient operating time for the sequential digit selecting circuit, and, while operated, temporarily opens at its break contacts PCS-1, PCS2, PCS-3, PCS-4 and PCS-5 the individual battery leads of the translator relays whereby to prevent a possible invalid registration, and also completes an operating path for relay ZX of the sequential digit selecting circuit (FlG. 6) traced from ground at the end-of-pulse circut (FIG. 5) make contacts PCS-6, (FIG. 5) and PCS-7 (FIG. 6) of relay PCS, break contact WX-l of relay WX, winding of relay ZX to battery. (Relay ZX together with relay WX are major items in controlling the sequence in which the translator is connected to the storage units; this will be further described subsequently.)

Relay ZX, operated, completes an operating path for relay DTi' of the central oflice trunk testing circuit (FIG. 8), which path is traced from battery, winding of relay DTI, make contact 13T-3 of relay DT, make contact ZX-l of relay ZX to ground.

Central Ojjice Trunk Seizure Gperation of relay DTL as above, connects the diode polarized relay bridge, comprising diodes 1&7 and 198 and relay DTZ (FIG. 8), across tip conductor 121 and lring conductor 122 toward the central oliice trunk, this connection being over a path including make contacts DTi-4 of relay DTl and DT-i of relay DT to the tip 12E; and over a path including make contact DTi-5 of relay DTL make contact DT-Z of relay DT, break contact CL-3 of relay CL and make contact DTi-6 of relay l DTI to the ring 122. Relay DTI, operated, also is effaster dialing which is feasible, and usually desired, on a direct dial central oce trunk call. (It should be noted that relay DT1 may also be operated, and the interdigital period changed, under different circumstances. For example in certain situations a central office trunk cord may be seized directly in which event relay CLA (FlG. 8) will operate as described above thereby completing through its make contact CLA-l an obvious operate path for relay DTI.)

Upon completion of outpulsing of the registered 9, the selector will seize an idle central otlice trunk and, when the seized trunk is ready to receive pulses, it will in line with its normal method of operation connect battery to the tip conductor 121 and ground to the ring conductor M2 (FiG. 8) which operates relay DT2 over the paths described in the preceding paragraph.

Operation of relay DTZ releases'at its DTZ-l break contact relay DT which, after operating as described above, was held through its make contact DT-S, break contact DT2-3r of relay DTZ and make contact CS-S or relay CS to ground. As previously pointed out above in connection with FlG. 5, at the time relay DT operated attendants lamp (FlG. l) was energized at Hutter from iiutter circuit 72, make contact DT-Z of the DT relay, break contact 'TF-l of relay TF, make contact C8-5 of relay CS and out over lead Kil-73. Now upon the release of relay DT, steady ground is substituted for the intermittent ground of flutter circuit 72 over a path from ground, break contact Dri-1 of relay D6, break contacts SS7- of relay S87, DT-fl of relay DT and TF-l of relay TF, make Contact CS-6 of relay CS over lead Kil-73; attendants lamp S5 now lighted at steady indicates start dialing to the attendant.

As previously described above under the section, Attendant Dials 9, the storage and digit selecting relay circuits are, in effect, recycled after the digit 9 has been dialed for seizure of a central oilce trunk, so that the iirst digit of the actual subscribers number when dialed will be stored in the first storage unit rather than the second.

Digit Selecting The sequential digit selecting circuit (FIG. 6) is utilized to connect the translator to the storage units (FIG. 4) in a properly controlled sequence. This control is exercised principally through the WX and ZX relays of the sequential digit selecting circuit and the RC and RC1 relays of the recycle circuit (FIG. 5).

The lirst digit path (contemplating recycle following the dialing of 9 as above described) extends from the ground stored on two-out-of-five reed switches of the ARS storage unit through break contacts SSI-1 to SSI-5, inclusive, of digiti selecting relay S81 to the operating windings of the corresponding two-outofi`1ve relays T0, T1, T2, T4 and T7 of the translator.

The second digit path extends from. the second storage unit BRS over paths including respective series connection of break contacts S82-1 to S82-5 of second digit selecting relay S82 and make contacts SSI-6 to SSI-1l) of the first digit selecting relay SSI.

The other digit paths are completed in a generally similar manner; for example the fourth digit path extends from the fourth storage mit DRS (not shown in detail) over paths including respective sefries connections of break contacts 884-1, 884-2, 884-3, 884-4 and 884-5 of the fourth digit selecting relay S84 and make contacts 883-6, SSS-7 883-8, SSS-9 and SSS-lll of the third digit selecting relay S83.

As pointed out above the PC and PCS relays (FIG. 5) operate following the completion of each digit; this causes operation of relay ZX of the sequential digit selecting circuit (FIG. 6). The iirst operation of relay ZX causes operation of sequential digit selecting circuit relay S81 (FIG. 6) over a path from battery, winding of relay S81, break contact DT-S of relay DT (which, as above described, released following operation of relay DTZ, FIG.

8), break contacts S82-ll of relay S82, 884-11 of relay S84 and SSl-lll of relay S86, make contact ZX-Z of relay ZX, make contact CS-l of relay CS to ground. Relay SSl, operated, steers the second digit recorded in storage unit BRS to the translator over the paths completed through its make contacts 881-6, SSI-7, SSI-8, SSl-9 and SSIl-lll, which paths as described above include break contacts of relay S82.

Release of the PCS relay sets up an operate path for relay WX (llG. 6) from ground, make Contact CS-9 of relay CS, break contact SS'7-7 of relay S87, break contact DT-n of relay DT, break contact PCS-8 of relay PCS make contact ZX-3 of relay ZX, break contactV WX-2 of relay WX, winding of relay WX to battery. Upon operation of relay WX, relay ZX holds over a path through make contact WX-S of relay WX, its own make contact ZX-S and over the remainder of the path just traced.

Upon the completion of outpulsing of the second digit relay PCS again operates and interrupts at its PCS-8 break contact the holding path just referred to for relay X which thereupon releases. Relay ZX, released, completes an operating path for the second digit selection relay S82, this path being from battery, winding of relay S82, break contact S82-l2 of relay S82, make contact SSl-ll o't relay SSl, break contactZX-4 of relay ZX, make contact CS-S of relay CS to ground. Operation of the second digit selection relay steers the third digit stored in unit CRS to the translator over an obvious path similar to those previously described.

Subsequent release of the PCS relay releases the WX relay (previously held through its make contact WX-4, lead 12d and make contact PCS-7 of relay PCS), which partially prepares the operate path of relay ZX for completion upon the next operation of relay PCS. The circuit continues to operate in this progressive stepping manner for selection ofy subsequent digits.

It will be noted that relay SSl, after operating as above described, locks up over la path from battery, its operating winding and make contact SSl-lll, break contact 887-9 of relay S87 and make contact CS-ll of relay CS to ground, and that relay S82, after operating, locks to the same ground through its own make contact S82-l5 and make con-tact 881-12 of relay SSl. Similarly relay S83, after operating over the path through make contact S82-13 of relay S82, locks to ground through its own make contact SSS-1l and make contacts S82-lll of relay S82 and CSl't) of relay CS to ground. Similarly, relay S84. after operating through make contact 883-12 of relay S83 and its own break contact 884-12, locks to ground through its make contact SSS-l, and relay SSS, after operating through make contact 884-13 of relay S84, locks to ground through its own make contact 885- 1l and make contacts 884-14 of relay S84 and CS-9 of relay CS to ground. In a similar manner relay S86, after operating through make Contact SSS-l2 of relay SSS, locks to ground through its own make contact SS5- lZ and make contacts 885-13 of relay S85 and CS-9 of relay CS, while relay S87 after operating through makev contact 886-13 of relay S86 locks to ground through its own make contact 887-8 and make contact CS-9 of relay CS.

Recycle and Guard In instances where the dialing information exceeds seven digits, such, for example, as a direct distance dialed call, the novel arrangement contemplated by the present invention is such that the rst tive storage units will be recycled, after operation of the seventh digit steering circuit relay, whereby to permit use of these storage units for the additional digits. However, the novel arrangement includes, as will be described in detail below, means for guarding against a premature release of the storage units in the event the attendants pushbutton dialing speed has too greatly outdis-tanced the outpulsing speed of the 1S register sender; specifically, if the sixth digit is pushbutton dialed before the fourth registered digit is being outpulsed.

Normally, i.e. assuming for the moment that the ou-tpulsing speed had kept in line with the dialing speed and the guarding procedure was not required, the recycle circuit (FlG. will function following registration of the seventh digit. Registration of the seventh digit causes operation of steering circuit relay D7 (FIG. 3) which, in turn, completes an operating path for relay RC (FIG. 5) traced from battery, Winding of relay RC, make contacts D7-l` of relay D7 and CS-lZ of relay CS to ground. Relay RC, operated, causes the release of all operated relays in storage units ARS to ERS as well as the release of steering circuit relays D1 to D5; this action results from the fact that the respective locking paths for the relays are opened at break contacts of the now operated RC relay. These paths over which the resective relays were held are similar and all need not be traced at this point. The previous locking path for the Dil relay, for example, was established from battery, make contact D1-14 and operating winding of relay D, lead 127, a respective two of the make contacts ARM-1, ARl-ll, ARE-1, ARA-1 and AR71 of the ARS storage unit depending upon the particular relays operated, lead L1 of the recycle circuit (FIG. 5), break contacts RC-l of relay RC and DTi-8 of relay DT1, make contacts CSJS of relay CS to ground; upon operation of relay RC, as above, this path is interrupted at its break contact RC4. rl`he previous locking paths for the operated relays ot the ARS storage units are similar to that of the D1 relay except that battery is found at the respective relay and the path includes a respective make contact ARQ-2, Alli-2, ARE-2, ARQ-2 or AR-Z; upon operation of relay RC these paths are interrupted at its break contact RC-l.

Following operation of relay SS' of the sequential digit selecting circuit and during a released interval ot' relay ZX, relay RC1 (FlG. 5) will operate from battery, winding of relay RC1, make Contact SS'-ltl of relay SS7, break contact .ZX-S of relay ZX, break contact SSl-ldlof relay SSL make contact (3S-11 of relay CS to ground, and upon operating will lock to ground through its own make contact RC1-1.

Release of the D to DS steering relays completes respective operating paths for auxiliary locking relays Ais1 to ALS of the recycle circuit (FlG. 5) from ground, through'respective break contacts D1-13 of relay D1, D24 of relay D2, Dil-1 of relay D3, Dlt-1 of relay D4 and DS-Zl of relay D5', the respective operating windings, and through make contact RC-Z of relay RC to battery. (lt should be noted here that relay D7 is held operated from battery, its make contact JD7-3 and operating winding, make contacts of the respective two operated relays in storage unit GRS, over lead L5 (FIG. 5) and make Contact CS-lfi of relay CS to ground, hence relay RC remains operated through make contacts D741 of relay D7 and CS-l?. of relay CS.)

The auxiliary locking relays AL1 to ALS, upon operating, lock from batteri, make contact RC-Z of relay RC, operating windings and respective make contacts AL1-1, Ala2-1, ALS-1, AL/land ALS-l, and make Contact CS-l of relay CS to ground; the auxiliary locking relays, operated, provide the following auxiliary locking paths for the storage unit relays which will be reoperated by dialing of the additional digits:

ARS-line L1, make Contact RFC-3 of relay RC, make contact ALI-1 of relay ALL make contact CS-13 of relay CS to ground;

BRS-dine LZ, make contact RC--t of relay RC, make Contact ALf-Z or relay ALE, make contact CS-19 of relay CS to ground;

GRS- line L3, make contact RC-S of relay RC, make Contact ALS-2 of relay ALE?, make Contact CS18 of relay CS to ground;

DRS-line L4, make contact RC-6 of relay RC, make contact ALs-2 of relay AIA, make Contact C3417 of relay CS to ground; and

ERS-line L5, make contact RC-7 of relay RC, make Contact ALS-2 of ALS, make contact CS-ld of relay CS to ground.

With regard now to the novel arrangement provided for guarding against a premature release of the storage units when the attendants dialing speed has been faster than the outpulsing rate, let us assume that the sixth digit is being pushbutton dialed before the fourth registered digit is being outpulsed. For this condition relays SSS and SS,7 will be released and relay D6 operated and a path will be completed therefor from tlutter circuit '72 (FIG. 5) break contact SSS-i4 of relay SSS, make contact Di-Z of relay D6, break contact SSi-l of relay SS?, break contact D11-4 of relay DT, break contact 'IF-1 of relay TF, make contact CS-e of relay CS and over lead KIR-73 to the attendants position (FIG. l) where it energizes attendants lamp 35 at flash as a Warning to the attendant to hold up dialing until the outpulsing of the fourth digit is completed. However, once the outpulsing of the fourth digit has been completed, relay SSS will operate and steady ground will then be applied through make contact 883-15 instead of the ground interrupted at Hutter frequency previously applied through break contact 555344; lamp 35 will now light at steady as a signal to the attendant to resume dialing. It should be noted that even though the attendant should attempt to override the flutter signal and continue dialing the circuit will not recycle prematurely since, in accordance with the novel arrangement contemplated by the invention, the operating paths for the auxiliary locking relays ALI to ALS are completed progressively through break contacts of the digit selecting relays. Thus, no auxiliary l-ocking relay of the group will operate until the corresponding digit selecting relay has released following outpulsing or" the preceding digit; for example auxiliary locking relay ALL@ will not operate until after the fifth digit has been outpulsed and relay D4 has released and closed the operating path for relay AL4 at break contact Dfi-1.

Sender Release When the attendant has completed pushbutton dialing the called number she depresses the E (end) key of the call transmitter 31 (FIG. 1) as an end-ot-code information; this operation applies ground to the 4 digit lead and operates a storage circuit register relay. On a 7-digit central office call the end-of-digit code will normally be registered in the ARS storage unit while in the instance of an ll-digit direct distance dialed code the endof-code digit 4 will normally be registered in the DRS storage circuit. When the cnd-of-code information is transmitted to the translator, under control of the sequential digit selector circuit, relay T4 operates and completes an operate path for the RLS relay of the release circuit (FG. 8) from battery, Winding of relay RLS, break contact 'F7-3 of relay T7, make contact 'T4-1 of relay T4, break contacts 'I2-3 of relay T2, 'F1-1 of relay T1 and TSJ; of relay T 0 to ground; relay RLS upon operating locks through its own make Contact RLSJL and make contact CS-Zil of relay CS to ground.

Relay RLS, operated, removes at its break contact RLS-2 the ground from lead CT-63 (FIG. 7) to the register sender link circuit 34, and establishes at its RLS-3 make contact an additional path for connection of ground to lead Ml3-o4 to the register sender link circuit. Removal of ground from lead CT-63 causes the register sender link circuit to function and remove ground from the CS-36 lead; this ground was previously supplied to the attendants lamp 3S, which now goes dark, and to relay CS of the seizure circuit, which now releases.

Release of relay CS removes battery from the previously described pulse counter, interdigital timing, endof-pulse train, and clear circuits and removes ground from the central oiiice trunk testing, pulse generator, sequential digit selector, recycle and ASB register circuits. Release of the PC relay in the end-of-pulse circuit (FiG. causes the release of relay PCS by opening the operate path at make contact 13C-t5. Release ot relay PCS releases relay RLS, previously held to ground (after release of relay CS) through its make contact RLS41 and make contact PCS-9 of relay PCS; this removes, at make contact RLS-3, ground from lead MiB-64 and the register sender is now in normal, idle condition.

Clear Operation Normally the operating winding of relay CL of the clear circuit (FIG. 6) is shunted by ground from any of the digit leads 0, 1, 2 or 4 over lead 131i and through its own break contact (L-4. However, there is ordinarily provided at a convenient location, for example at the attendants position, a release key (not shown) the operation of which is eiective to apply ground only to the 7 digit lead; this ground applied over lead 132 will pass through the operating winding of relay CL, make contact CS-Zl of relay CS to battery thereby operating relay CL, which then locks to ground through its make contact CL-S and opens lead 131 at break contact (lL-4. Relay CL, operated, removes at its CL-6 break contact negative battery from electrode 68 of timer tube 71, opens at its break contact CL-3 (FlG. 8) the connection to ring connector 122, disconnects negative battery at its CL-7 break contact and connects at its CL48 make contact capacitor 133 into the timing path whereby to cause a clearing time (loop open) of approximately two seconds, and transfers at its CL-9 make contact the main anode circuit of timer tube 7l through break contact CLL-1 to one side of the winding of relay CLL. Upon completion of the 2-second clearing time tube 7ll ionizes and operates relay CLL. Relay CLL, operated, extinguishes tube 71 by opening at break contact CLL-1 the main anode path and reconnecting at make contact CLL-2 negative battery potential to electrode 68. Operation of relay CLL also completes at its make contact CLL-3 a path for operating relay RLS of the release circuit (FIG. 8) which causes the circuit to restore to normal as above described.

Invalid Code Check Contacts of the translator relays Tt), Tl, T2, T4 and T7 controlling the operating paths of the TF relay in the trouble finder circuit (FIG. 8) will cause the operation of the TF relay Whenever an improper code is transmitted, that is a code other than two-out-of-iive with the exceptions of the single 4 and 7 codes which are valid codes. Provision of the break contacts T7-4 of relay T7 and 'f4-2 of relay T4 prevent the operation of relay TF when either codes 4 or 7 are transmitted. However, this is not true of any other single codes. For example, let us assume rst that relay VTil operates by the single code 0. We then have a path from ground, make contact Tti-Z of relay Tti, break contacts Tl-Z of relay T1, T12-4 of relay T2, Tt-2 of relay T4, T7-4 of relay T7, winding of relay TF to battery; relay TF operates over this path. However, if the code 0 is properly combined with codes 1, 2, 4 or 7 the path will be open at the corresponding break contact and the relay will not operate. For further illustration, assume that code 2 is transmitted singly, relay TF will then be operated over a path from ground, break con- Ttl-S of relay T0, break contact Tl-S of relay T1, make t contact T2-5 of relay T2, break contacts T4-2 of relay T4 and T7-4 of relay T7, Winding of relay TF to battery. Assuming now that We have an improper code combination of 1, 2, and 4, we tind an operating path for relay TF completed through break contact Til-3 of relay Ttl, and rnake contacts Tl-i of relay T1, 'FZ-6 of relay T2 and T4-3 of relay T4.

' Improper codes as above may result from improper pushbutton operation (two or more buttons depressed simultaneously), shorts or opens in the leads, stuck relay or the like. When the TF relay operates as above described, interrupted ground IPM) is applied through make contacts TF-S of relay TF and CS-6 of relay CS to lead lill-73 (FlG. 5) which causes the attendants lamp 35 (FIG. l) to flash at the rate of 120 IPM. This indicates a trouble condition to the attendant who may then clear the circuit by operation of her release key as described above under Clear Operation.

While a specitc embodiment of the invention has been selected for detailed disclosure, the invention is not, of'

course, limited in its application to the embodiment disclosed. The embodiment which has been described should be taken as illustrative rather than restrictive thereof.

What is claimed is:

l. in an automatic telephone system, a call transmitter for transmitting a plurality of sequentially related digits the first of which may be a central oirice trunk seizure code, a register sender and a connecting circuit, said register sender including a plurality of register units for storing in turn the respective digits transmitted by said call transmitter, means included in said register sender for outpulsing the stored digit information to said connecting circuit, and means, eiiective upon registering in the first of said register units and subsequently outpulsing a central otiice trunk seizure code digit, for recycling the rst register unit whereby the digit next transmitted is stored in said first register unit.

2. In an automatic telephone system, a call transmitter for transmitting a plurality of sequentially related digits the first of which may be a central oiice trunk seizure code, a register sender and a connecting circuit, a plurality of individual register units included in said register sender for storing the digits transmitted by said call transmitter, means for outpulsing the stored information to said connecting circuit, means for directing each transmitted digit to the respective register units in turn, and means, effective upon registering in the first of said register units, and subsequently outpulsing, a central oice trunk seizure code digit for rendering said directing means ineilective with respect to the digit next transmitted whereby such digit is stored in said rst register unit.

3. In an automatic telephone system, a call transmitter for transmitting a plurality of sequentially related digits greater in number than seven, a register sender and a connecting circuit, said register sender including seven register units for storing the respective seven digits first transmitted by said call transmitter, means included in said register sender for outpulsing the stored digit information to said connecting circuit, recycling means etective upon transmission by said call transmitter of the seventh digit for restoring the first live of said register units to normal for reception of additional digits, and means for preventing the operation of said recycling means if a predetermined number of the stored digits have not been outpulsed when the sixth digit is transmitted by said call transmitter.

4. ln an automatic telephone system, the combination defined by claim 3 further characterized in that said predetermined number is a number not less than four.

5. ln an automatic telephone system, the combination defined by claim 3 further characterized in the provision of signaling means for indicating that said predetermined number of stored digits have not been outpulsed prior to transmission of the seventh digit.

6. In an automatic telephone system, an attendants position, a call transmitter at said position for transmitting a plurality of sequentially related digits the iirst of which may be a central otlice seizure code, a register sender and a connecting circuit, a plurality of individual register units in said register sender for storing in turn the respective digits transmitted by said call transmitter,

means included in said register sender for outpulsing the stored digit information to said connecting circuit at a predetermined interdigital rate, and means etective upon transmission of a central otce seizure code for changing said predetermined interdigital rate by a specific amount.

7. In an automatic telephone system, the combination dened by claim 6 further characterized in that said lastmentioned means inciudes a capacitor connected in a timing circuit and means for changing the effective value of said capacitor.

8. In 'in automatic telephone system, the combination dened by ciaim 7 further characterized in the provision of additional means eiliective upon direct seizure of a central oice truuk for operating said effective value changing means.

9. in an automatic telephone system, an attendants position, a call transmitter at said position for transmitting a plurality of sequentiaily retated digits greater in number than seven the iirst of Which may be a central oice seizure code, an attendants signal lamp at said position, a battery potential connected to one side of said lamp, a register sender and a connecting circuit, means included in said register sender for storing the respective seven digits rst transmitted by said call transmitter, means for outpulsing the stored digit information to said connecting circuit, a source of ground interrupted at a predetermined frequency, a source of steady ground, means effective upon seizure of a central oice trunk responsive to transmission of a central olce trunk seizure code for connecting said source of interrupted ground to the other side of said attendants lamp whereby to flash said lamp as a stop dialing indication to the attendant, means eiiective when the seized trunk is in condition to receive puises for disconnecting said source of intermittent ground from said other side or" the attendants lamp and for connecting thereto said source of steady ground whereby to light said iamp steadily, and means etective upon transmission of the sixth digit by said call transmitter before a predetermined number of the registered digits have been outpulsed for connecting said source of interrupted ground to said other side of said attendants lamp to again flash said lamp as a stop dialing indication to the attendant.

10. In a telephone system, the combination deined by claim 9 further characterized in the provision of means effective upon the outpulsing of said predetermined number of registered digits for disconnecting said source of interrupted ground and for connecting said source of steady ground to said other side of said attendants lamp whereby to light said lamp steadily as a resume dialing indication to the attendant.

11. in an automatic telephone system, a call transmitter for transmitting a plurality of sequentially related digits greater in number than seven, a register sender and a connecting circuit, seven register units in said register sender for storing the respective seven digits first transmitted by said cail transmitter, respective locking circuits for said register units, means inciuding seven digit directing relays for directing each respective transmitted digit .to the respective one of said register units, means in said register sender for outpulsing the stored digit information to said connecting circuit, recycling means effective upon transmission by said call transmitter of the seventh digit for restoring the rst ve of said register units to normal for reception of additional digits, and means for preventing the operation ci said recycling means if a predetermined number of the stored digits have not been outpulsed when the sixth digit is transmitted by said call transmitter.

12. in an automatic telephone system, the combination deiined by claim 11 further characterized in that said recycling means inciudes auxiliary locking paths for said register units.

13. 1n an automatic telephone system, the combination 'defined by claim 12 further characterized in that said pre- {venting means includes paths through break contacts of respective ones of said diUit directing relays for establishing said auxiliary locking paths.

References Cited in the file of this patent UNITED STATES PATENTS 

1. IN AN AUTOMATIC TELEPHONE SYSTEM, A CALL TRANSMITTER FOR TRANSMITTING A PLURALITY OF SEQUENTIALLY RELATED DIGITS THE FIRST OF WHICH MAY BE A CENTRAL OFFICE TRUNK SEIZURE CODE, A REGISTER SENDER AND A CONNECTING CIRCUIT, SAID REGISTER SENDER INCLUDING A PLURALITY OF REGISTER UNITS FOR STORING IN TURN THE RESPECTIVE DIGITS TRANSMITTED BY SAID CALL TRANSMITTER, MEANS INCLUDED IN SAID REGISTER SENDER FOR OUTPULSING THE STORED DIGIT INFORMATION TO SAID CONNECTING CIRCUIT, AND MEANS, EFFECTIVE UPON REGISTERING IN THE FIRST OF SAID REGISTER UNITS AND SUBSEQUENTLY OUTPULSING A CENTRAL OFFICE TRUNK SEIZURE CODE DIGIT, FOR RECYCLING THE FIRST REGISTER UNIT WHEREBY THE DIGIT NEXT TRANSMITTED IS STORED IN SAID FIRST REGISTER UNIT. 